Method of making blood pressure bags and other articles



March 16, 1943. G. WINDER METHOD-OF-MAKING BLOOD PRESSURE BAGS AND OTHERARTICLES Filed Aug. 17, 1940 2 Sheets-Sheet 1 2-2 ENfUL 550292 L-ZZ/z'naaa.

March 16,1943. L, WINDER 2,313,792

METHOQ-OF-MAKING BLOOD PRESSURE BAGS AND OTHER ARTICLES Filed Aug. 17,1940 2 Sheets-Sheet 2 550525 .2 MHUEJL.

Patented Mar. 16, 1943,

METHOD OF MAKING BLOOD PRESSURE BAGS AND OTHER ARTICLES George L.Winder, Cuyahoga Falls, Ohio, assignor to American Anode Inc., Akron,Ohio, a corporation 01' Delaware Application August 17, 1940, Serial No.353,145

6 Claims.

This invention relates to hollow rubber articles provided withcommunicating tubes extending therefrom and especially to blood pressurebags embodying novel constructional features and to economical andefllcient procedure for manufacturing such articles. The invention willbe described in detail with reference to the accompanying drawings ofwhich:

Fig. 1 is a sectional elevation illustrating a preliminarystep in themanuiacture of a tube as sembly employed in the present invention andshowing an auxiliary deposition form immersed in a liquid rubbercomposition for receiving a coating of rubber.

Fig. 2 is a perspective view illustrating a further step in the processand showing the tube assembly being removed from the auxiliarydeposition form.

Fig. 3 is a sectional elevation illustrating a further step in theproces sand showing the tube assembly associated with a principaldeposition form and the composite assembly immersed in a liquid rubbercomposition for receiving a coating of rubber.

Fig. 4 is a perspective view showing the composite assembly of Fig. 8with a rubber coating thereon and further illustrating the step ofslitting a portion of the coating to permit removal of the principalform.

Fig. 5 is an elevation illustrating thestep of removing the rubbercoating from the principal deposition form.

Fig. 6 is a perspective view, partially broken away and sectioned forclarity of illustration, showing the coating after removal from theprincipal form and further illustrating a preliminary step in sealingthe slit in the coating.

Fig. 'l is a sectional elevation illustrating a further step in sealingthe slit and showing an end portion of the coating immersed in a liquidrubber composition.

Fig. 8 is a perspective view showing a finished bloodpressure bag madein accordance with the present invention.

Fig. 9 is a vertical section taken on line 9-9 of Fig. 5.

Fig. 10 is a fragmentary elevation, broken away and sectioned, showingan end portion of a blood pressure bag embodying a modification of theinvention in which a reenforclng element is included in the region ofthe slit.

Equipment used by Physicians for determining the blood pressure ofpatients includes a unit known in the art as a blood pressure bag. Suchblood pressure bags customarily are made of rubber or analogous materialand include a generally rectangular flat hollow bag B and a pair ofcommunicating tubes T, T extending from one of the longer edges of thebagat a position adjacent one end thereof as indicated in Fig. 8.According to the present invention, such a blood pressure bag is made bya process in which a tube assembly is first formed independently, afterwhich the bag portion is formed in contiguous cohering relation with aportion of the tube assembly.

To form the tube assembly, I utilize an auxiliary deposition formindicated generally by the numeral Hi. The auxiliary form l0 includes arelatively small trapezoidalplate member i I provided with two rod-likestems l2, l2 extending fromone edge of the plate member H in the planeof the plate, the stems i2 corresponding in size and length to theinterior diameter and length of the tubes desired in the blood pressurebag. The form i0 may have a supporting member such as the hook I3extending from the opposite edge of the plate. To produce the tubeassembly, the auxiliary form 10 is coated with rubl her as by immersingthe form in a liquid rubber composition such as any suitably compoundedlatex L as illustrated in Fig. 1. Desirably the form I0 is pre-coatedwith a composition adapted to coagulate latex compositions as describedin U. S. Patent No. 1,908,719, and such coagulant composition desirablyshould contain a powdery separating material. as described in U. S.Patent No. 1,924,214. The form i0 is completely immersed in the latex asshown in Fig. 1 and ispermitted to remain therein until a rubber depositfrom .015 to .025" (when finished) has been deposited over the entireform. The form then desirably is raised until the liquid level of thelatex is just below the edge of the plate member I i and deposition onthe immersed stems I2 is then con tinued until the total rubber depositon the stems is from .030 to .060" thick (when finished). Such continueddeposition may be effected by progressive action of coagulant initiallyapplied to the form, or'the stems I! may be re-dipped a number of times,either with or without intermediate coagulant treatments, to build upthe desired thickness of rubber. The form in together with the depositedrubber coating is then removed from the latex and the rubber deposit isdried but not vulcanized. The rubber coating is then slit around the topedge of the plate I l to permit removing the tube assembly from the formas cated at I, 24.

parallel flaps. As will appear more clearly later,

the flaring member IE will constitute a'reinforcing element in thefinished bag. To insure a neat product, the exposed end of the elementIt desirably should be trimmed smoothly as along the semi-circulardotted line shown in Fig. 2 and indicated by the numeral I6.

I then provide a principal deposition form including a main portion llof generally flat rectangular configuration adapted to form the bagportion of the final product. The principal form also is provided withtwo rod-like stems l8, l8 which extend outwardly in the plane of theform from one of the longer edges of the main portion H at a positionadjacent one end thereof as shown in Fig. 3. The stems l8 desirablyshould be somewhat longer than the rubber tubes ll of the prepared tubeassembly, but otherwise should correspond in size to the tubes.

I next place the prepared tube assembly on the principal form by slidingthe tubes l4 down over the stems l8 until the flaring flange orreinforcing element l5 embracesclosely the portion of the main formadjacent the bases of the stems l8 as may be seen more clearly in Fig.3. Desirably the underside of the reinforcing element I5 is cemented tothe form H by means of a thin coating of rubber cement or other suitableadhesive which will prevent seepage of liquid rubber composition betweenthe two members during subsequent operations while permitting readyremoval of the completed article including the element IS. A suitablesupporting, clamp I9 is then attached to the extending ends of the stemsI8 and the composite assembly of the principal form with the tubeassembly thereon is immersed in a liquid rubber composition,

such as a suitably compounded rubber latex L, and a coating of rubber25, for example, about .025" thick is deposited over the entire assemblyincluding the exposed portions of the principal form and the outersurfaces of the tube assembly. As before, such deposition may befacilitated by the use of any appropriate coagulant for latex. Theassembly with its over-all coating of rubber is then removed from thelatex and the rubber is dried, but not vulcanized.

To permit removal of the principal form, I then slit a portion of therubber deposit 25, preferably along the major'length of the shorter edgeof the deposit removed from the tube assembly. Such slittingconveniently may be accomplished simply by progressively pressing aheated cutting element 20 or other suitable instrument against therubber along the edge (Fig. 4) The principal form is then removedthrough the opening made by the slit by doubling the rubber coating backoverthe form as shown in Fig. 5, and stripping the tubes from the stems.

To seal the opening made by .the slit, the cut edges at the slitpreferably are coated with rubber cement or other rubber adhesive asindicated at 2| (Fig. 6) and the cemented edges are pressed intoabutting relation. To insure against leakage at the seal and toreinforce the seal against failure when the bag is inflated, areinforcing cap of rubber 22 is produced thereover as by immersing theend portion, for example about one inch, of the bag in latex L or otherliquid rubber composition as shown in Fig. 7. This pro cedure may berepeated several times to build up a rubber cap of any desiredthickness.

It is also possible to utilize a coagulant to produce a heavier cap witha lesser number of dips and the coagulant may be applied to the entirearea to be capped or to a desired restricted portion thereof. In thelatter case, the cap will be thicker over the area to which coagulantwas applied.

Finally, the entire article is thoroughly dried and vulcanized byheating in the usual manner to produce a finished blood pressure bag asshown in Fig. 8.

For further reinforcing the seal at the slit, when desired, a strip oftextile fabric 23 (Fig. 10) or other reinforcing material may be placedover the slit prior to application of the rubber cap 22, or the fabricstrip may be interposed between any of the successive depositsconstituting the cap 22. In either case, the fabric 23 preferably ispre-treated' with latex or other rubber composition to secure moreperfect anchorage in the rubber.

It will be appreciated from the foregoing that a blood pressure bag orother article produced tubes T, T, extending therefrom and that thereinforcing element I5 is attached to the'interior face of the wall 25of the bag and is continuous with the inner portion H of the tubes T, asmore clearly shown in Fig. 9. The outer portions of the tubes T arecontinuous with the wall 25 of the bag B so that an unusually strong andessentially unitary structure is produced which effectively resistsfailure heretofore experienced at the junction between the tubes and thebag. Furthermore, the products of the present invention include areinforcing cap over the slit at the end of the bag which insureseffective sealing and reinforcement against failure upon inflation. Thecap also serves to provide a balanced appearance. It will further beappreciated that the constituent parts of the articles cohere and forman essentially unitary structure, although the several individual partsmay still be identified in the finished product.

The term rubber has been used in a generic sense to include not onlynatural Hevea rubber but also all analogous natural and syntheticrubbers and rubber-like materials.

While the invention has been described in considerable detail inconnection with the menu-- facture of blood pressure bags, theprinciples herein set out obviously may be applied with advantage in themanufacture of numerous other articles. It will likewise be understoodthat many modifications and variations in details of the procedure andmaterials described may be efiected without departing from the spiritand scope of the invention as defined by the appended claims.

I claim:

1. The method of making a blood pressure bag or similar article whichcomprises providing a principal form having a flat rectangular portionand a stern projecting outwardly from an edge thereof, producing, bydeposition from a liquid rubber composition, a unitary tube assemblyincluding a tubular member terminating in a flaring reinforcing elementcontinuous therewith,

mounting the tube assembly on the principal form with the tubular memberon the stem and the flaring-reinforcing element embracing theflat'portion of the principal form, coating the 2,313,702 assembly withrubber, slitting the rubber coating at a point removed from the tubeassembly, removing the form through the slit, applying rubber adhesiveto the cut edges at the slit, abutting the edges, and coating the regionabout the slit with rubber.

2.,The method of making a blood pressure bag or similar article whichcomprises providing a principal form having a flat rectangular portionand a stem projecting outwardly from an edge thereof, producing, bydeposition from a liquid rubber composition, a unitary tube assemblyincluding a tubular member terminating in a flaring reinforcing elementcontinuous therewith, mounting the tube assembly on the principal formwith the tubular member on the stem and the flaring reinforcing elementembracing the flat portion of the principal form, coating the assemblywith rubber, slitting the rubber coating at a point removed from thetube assembly, removing the form through the slit, and sealing the slit.

3. The method of making a hollow rubber article having a communicatingtube extending therefrom which comprises providing a principal formhaving a flat rectangular portion and a stem projecting outwardly froman edge thereof, producing, by deposition from a liquid rubbercomposition, a unitary tube assembly including a tubular memberterminating in a flaring reinforcing element continuous therewith,mounting the tube assembly on the principalform with the tubular memberon the stem and the flaring reinforcing element embracing the flatportion of the principal form, coating the assembly with rubber, andremoving the form from within the article.

' 4. The method of making a hollow rubber article having a communicatingtube extending therefrom which comprises providing a form having a mainportion shaped to form the hollow article proper and a stem extendingoutwardly therefrom, producing a unitary tube assembly including atubular member terminating in a flaring reinforcing element continuoustherewith, mounting the tube assembly on the principal form with thetubular member on the stem and the flaring reinforcing element engagingthe main portion of the form, coating the assembly with rubber, andremoving the form from within the article.

5. The method of making a hollow rubber article having a communicatingtube extending therefrom which comprises providing a form having a mainportion shaped to form the hollow article proper and a stem extendingoutwardly therefrom, producing a unitary tube assembly including atubular member terminating in a flaring reinforcing element continuoustherewith, mounting the tube assembly on the form with the tubularmember on the stem and the flaring reinforcing element engaging the mainportion of the form, temporarily adhering the reinforcing element to theform, coating the assembly with rubber, and removing the form fromwithin the article.

6. The method of making a hollow rubber article having a communicatingtube extending therefrom, which comprises producing a tube assembly ofrubber material comprising a tubular member and a flaring reinforcingelement continuous therewith, and depositing rubber material from aliquid rubber composition to produce a hollow body in part in contiguousrelation with the flaring reinforcing element and thereby to associatethe tube assembly with the hollow body.

, GEORGE L. WINDER.

